Resumo

A method for speciation of vanadium in solid samples was developed for quantification of vanadium( + 5) in solid samples of sediment Certified Reference Materials (CRM) PACS-2 and MESS-3 (Trace Elements in Sediments) of known total vanadium content. The method relies on a classical analytical chemistry procedure based on leaching water-insoluble vanadium( + 5) compounds from the solid state into solution using Na2CO3 followed by electrothermal atomic absorption spectrometry (ET-AAS) detection. The total amount content of vanadium was determined after complete digestion of the CRMs and found to be 132 ± 5 and 245 ±12 μg g-1 in PACS-2 and MESS-3, respectively, in good agreement with the certified values of 133±6 μg g-1 and 243 ± 12 μg g-1. The concentrations of vanadium(+5) were determined to be 25 ± 3 μg g-1 and 13 ± 2 μg g-1 in PACS-2 and MESS-3, respectively. These results were verified by the method of standard additions for which quantitative recoveries (100±2 and 97 ± 3 %, one standard deviation, n = 3) were obtained for spikes added to PACS-2 and MESS-3, respectively. Approximately 18.8 % of the total vanadium content of PACS-2 and 5.3 % in MESS-3 is in the form of vanadium(+5) species.